Hydrophobic fluoropolymer thin films were deposited on Si(100) substrates by plasma polymerization of allylpentafluorobenzene (APFB) under different glow discharge conditions, and in the presence and absence of Ar plasma pre-activation of the substrate surfaces. The FTIR and X-ray photoelectron spectroscopy (XPS) results suggested that the plasma polymerization proceeded mainly through the C=C bond of APFB, and the fluorinated aromatic structure in the deposited polymer films was preserved to different extents, depending on the radio-frequency (RF) power used for plasma polymerization, The use of a low RF power (similar to5 W) readily resulted in the deposition of thin films having nearly the same fluorinated aromatic structure as that of the APFB homopolymer. For the plasma-polymerized APFB (pp-APFB) films deposited on the Ar plasma-pre activated Si(100) surfaces, solvent extraction results suggested that the pp-APFB films became covalently tethered onto the silicon substrate surfaces. Thermogravimetric (TG) analysis results indicated that the thermal stability of the pp-APFB films had been enhanced substantially after annealing at 270 degreesC in a vacuum oven.